Baxi Avanta Plus System boiler

The technically advanced Baxi Avanta Plus System boiler is the perfect choice for larger properties with two or more bathrooms.  It combines high performance with simplicity, giving you all the heating and hot water you need while helping to reduce fuel bills.

Please note: warranty and purchasing information on this site applies to the UK only. For information on how to buy these products in the Republic of Ireland, please visit Baxi Potterton Myson.

Avanta Plus System

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  • SEDBUK (2005) A high efficiency modulating boiler
  • Available in 18, 24 & 30kW outputs
  • Available with a 2 year parts and labour warranty as standard
  • Extended warranty options available*. Ask your installer for details
  • Lightweight and compact design
  • Optional natural gas to LPG kits available for off mains gas areas

*Terms and conditions apply. Ask your installer to visit for more information

Avanta Plus systemA: Boiler width = 400mm

B: Boiler height = 670mm

C: Boiler depth = 300mm

D: Side clearance = 5mm

E: Upper clearance = 250mm

F: Lower clearance = 250mm

G: Front clearance = 600mm for servicing

  • Only available from independent merchants
  • Mounting plate includes taps for quick and easier installation
  • Fully compatible with the Multifit fluing system
  • Optional stand off frame for upward piping
  • Boiler frost protection for flexible siting e.g. garage or utility
  • System bypass protects against overheating without external bypass
  • Clear and visible pressure gauge, front facing for ease of commissioning and use
  • Free product training
  • Register on the works loyalty scheme
  • Market-leading support from our dedicated sales team for the independent market


Unit of Measure Baxi Avanta Plus System 18 Baxi Avanta Plus System 24 Baxi Avanta Plus System 30
Part number (boiler only) 7604562 7604563 7604564
Standard Horizontal Flue 720598701 720598701 720598701
Concealed User Controls No No No
On/Off Switch with Reset Yes Yes Yes
User Adjustable CH Temperature Yes Yes Yes
Gas Supply Pipe Size mm 22 22 22
Natural Gas Yes Yes Yes
LPG (Butane/Propane) Optional Optional Optional
Gas Consumption Natural Gas (LPG) m3/hr 1.9(0.7) 2.3(0.85) 3.2(1.2)
Heat Output Central Heating (minimum/maximum) kW 5.8 / 18.3 5.8 / 22 6.1 / 30
SEDBUK (2005) Rating Band A A A
Seasonal Efficiency NG/LPG (2005) % 90.3 90.3 90.4
Seasonal Efficiency NG/LPG (2009) % 88.8 88.9 88.9
N0x Class 5 5 5
N0x Levels mg/kWhr 37 37 37
Electrical Supply Volts / Hz 230 / 50 235 / 50 230 / 50
Permanent Live Required Yes Yes Yes
Fitted Electrical Cable Yes Yes Yes
Power Consumption Watts 115 115 115
External Fuse Rating Amps 3 3 3
Ingress Protection Rating (without mechanical timer fitted) IP X4D X4D X4D
24-hour Pump Exercise Yes Yes Yes
Integral Boiler Only Frost Thermostat Yes Yes Yes
Mechanical and Hydraulic
Mounting plate including taps Yes Yes Yes
CH Flow and Return Pipe Size mm 22 22 22
Condensate Discharge Pipe Size Inch 3/4 3/4 3/4
Minimum Operating Water Pressure bar 1 1 1
Safety Discharge Pressure bar 3 3 3
Integral Expansion Vessel Capacity litres 8 8 8
Filling Loop Included Yes Yes Yes
Concentric Flue System
Standard Telescopic Horizontal Flue Kit Length mm 315 - 500 315 - 500 315 - 500
Max Equiv Length Horizontal/Vertical 60/100 / (80/125) m 6 (29) 6 (29) 6 (29)
Equivalent Length per 135' Bend (60/100) & (80/125) m 0.5 0.5 0.5
Equivalent Length per 93' Bend (60/100) & (80/125) m 1 1 1
Max Installation Lift Weight kg 29.0 29.0 32.0


Additional heating and hot water controls can improve the overall performance of your heating system by as much as 13% (according to ErP Directive drafts), dramatically reducing the amount of fuel you use - and the amount you pay for your energy bill.
For more information please speak to your installer as they will be able to advise you on the controls that are right for you.

  • iSense RF 7-day digital timer is a multi-functional 7 day programmable temperature control that delivers the best efficiencies and increased cost savings.  Provides up to 6 daily heating periods, day/night adjustments, frost protection and summer temperature settings
  • qSense digital room thermostat which programmes the boiler to control your room temperature. Can be used with the iSense for even greater comfort and savings
  • Internal digital time clock two channel, with 24 hour/7 day programmer for separate heating and hot water time control
  • Outside weather sensor (wired) monitors outside temperatures and optimises boiler performance efficiently and economically for your increased comfort.  No service or maintenance required

Baxi's system boiler range has product literature for both homeowners and installers available. To learn more about the Baxi Avanta's advanced controls, or gain knowledge of how to install a Baxi Avanta, download our documents.

  • Avanta brochure (PDF 0.72MB, 09/10/2014)
  • Find an installer or find a boilerWe have Gas Safe Registered installers all over the UK who will be able to give you a quote for the installation of your new boiler. To use our handy find an installer tool, simply enter a few details and we'll do all the hard work for you by contacting them on your behalf.

    The installer will get in touch to arrange a site survey to give you a competitive, no obligation quote.

    Unsure of what type of boiler you need?

    Try our find a boiler tool. It will ask you a few key questions relating to your heating and hot water requirements and recommend a suitable gas boiler.

     For more information about this type of boiler, please use the links below:

    FAQs about system boilers

    Compatible controls

    Brochures & guides

    Download brochures and manuals for your product

    Download documents about the Baxi Avanta Plus System, from installation information, to brochures and user guides.